Abstract
BACKGROUND: The spectrum of cystic renal neoplasms includes both benign and malignant tumors and the order is as follows: benign multilocular cyst, multilocular cystic renal cell cancer and cystic renal cell cancer. Gross similarities among multicystic tumors of the kidney may cause conflict in the diagnosis and treatment of these lesions. RESULTS: We report a 53-year old male patient who presented with a mild persistent left flank pain and a painful left renal mass. After a series of examinations including abdominal ultrasound, intravenous pyelography and computed tomography, he underwent radical nephrectomy. Microscopic examination of the resected tissue showed the typical characteristics of a cystic nephroma. Immuno-histological staining of the epithelium of the tumour with CK 19 suggested an aberrant renal tubular differentiation. CONCLUSION: Cystic nephroma is a relatively rare benign lesion of the kidney. Since 1892, only 200 cases have been reported in the international literature. The non-specific clinical findings and the poor contribution of imaging examinations make the preoperative distinction from other cystic renal neoplasias difficult. Final diagnosis can be established in the histopathological examination of the completely rejected tumor in the pathology laboratory.